1. Field of the Invention
The present invention relates to a plug-and-socket connector for optical fibres.
Plug-and-socket connectors of this type are employed for the optical coupling of two optical fibres or for the optical connection between an optical fibre and a light source such as a laser or a light-receiving instrument such as a laser catheter adapted to be introduced into the human body. Apart from the aforementioned applications there are, of course, additional applications in the field of medicine or engineering, e.g. in the field of material processing or laser labeling.
The general term xe2x80x9coptical fibrexe2x80x9d as used here is to be understood to denote a single fibre (for mono-mode or multi-mode operation) or a bundle of fibres, which consist of any material whatsoever, in the description presented below.
2. Prior Art
Plug-and-socket connectors for optical fibres are generally common and are manufactured, for instance, by the company of Faseroptik Henning GmbH, Allersberg (Germany) in many different types. For an explanation of all terms not described here in more details, and with respect to potential applications, explicit reference is made to these series-produced plug-and-socket connectors.
Plug-and-socket connectors may comprise, for instance, a socket wherein the optical fibre to be coupled is maintained as well as a plug which receives the element to be connected to the optical fibre, such as another optical fibre or an optical element or a joining optical system, respectively.
In the known plug-and-socket connectors a centering element is provided in the connector, into which the optical fibres are inserted when the socket and the plug are connected.
Particularly when the plug-and-socket connector is intended to enable the coupling of the optical fibre with high efficiency, it is necessary that the plug-and-socket connector and the centering element provided therein, be high-precision elements that cannot be manufactured, as a rule, by processes such as an injection moulding technique.
The known plug-and-socket connectors are therefore complex and hence expensive. The current plug-and-socket connectors are thus too expensive, particularly for applications such as disposable laser catheters.
Above all, however, the known plug-and-socket connectors are not suitable for coupling optical fibres of different diameters because the centering elements are each designed only for optical fibres having a particular diameter.
3. Object of the Invention
The present invention is now based on the problem of improving a plug-and-socket connector in such a way that a high-precision coupling of optical fibres having a varying diameter will be possible at a comparatively low expenditure in terms of structure.
One inventive solution to this problem is defined in Patent claim 1. Improvements of the invention are the subject matters of claims 2 et seq.
In accordance with the invention the plug comprises at least three wrap springs. In the released condition the wrap springs are straight; as a result of the locking rotating movement they surround the fibre for centering it. It is also possible, of course, to provide four or more wrap springs.
Due to the inventive wrap-around longitudinal centering, a centric connection of fibres even of different diameters is achieved, which may vary by several factors in particular. Moreover, the centering effect is even achieved with high precision when the individual elements have a comparatively low precision as it is common on injection-moulded parts.
The locking rotating movement may be performed in particular by turning the socket. When the socket is turned one part of the plug is rotated, for instance, on which one end of the wrap springs is retained.
If a funnel-shaped centering element is arranged ahead of the wrap springs along the direction of insertion, the insertion of the optical fibres is facilitated. This centering element may be held on that part, in particular, on which one end of the wrap spring are retained.
It is particularly preferable to provide a second fibre holder for another optical fibre or an optical systemxe2x80x94such as an imaging systemxe2x80x94in the plug, with the wrap springs centering the optical fibre to be coupled on the center axis of this system. The other end of the wrap springs may also be mounted on the second fibre holder.
To enable the operation with parts that are manufactured with a comparatively low precision, it is moreover expedient to provide the second fibre holder with adjusting means.
In another embodiment it is preferred that the plug and the socket can be locked by means of a snap-in connector which may comprise a ball in particular, so as to achieve a reliable plug-in connection.